The problem at hand concerns the unwinding of coils of relatively rigid metallic wire easily, rapidly and without mishap for immediate use in machines which may take it with sudden stops and starts.
The wires in question are essentially, but not exclusively, made of non-ferrous metals, principally aluminum and copper. At present, those metals are continuously cast and rolled into wire at very high speed by the well known process of continuous casting and rolling on a wheel partially surrounded by a flat metal belt.
In order to wind such wire rapidly as it is manufactured, without the rhythm being slowed down, it frequently is necessary to abandon the conventional process of circular winding, by spooling about a horizontal axis supporting an expansible mandrel (FIGS. 1 and 2), and to replace it by a flat helicoidal winding about a vertical axis on a receiver (pallet or the like), with or without a central mandrel 1 or outer basket, which produces a winding in horizontal hypocycloidal layers (FIGS. 3, 4, 5 and 6).
Various forms of windings may be obtained depending on shape, length, eccentricity of the turns, speed of rotation of the tube forming the helix, distribution, the mean diameter and the thickness of the layers obtained by more or less slow, continuous or sequential rotation of the plate, the pallet or the receiver mandrel. The more or less thick layers of wire may be disposed flat in various ways, viz. as a spiral, rosette, etc. as shown in FIGS. 3, 4, 5 and 6. All such rapid flat windings have a much lower weight/volume ratio than do the circular windings wound by spooling on a horizontal mandrel (FIGS. 1 and 2).
It should be pointed out that the coils 2, 3 or 4 (FIGS. 1-6) of so-called machine wire constitute an intermediate stage between rolling and wire-drawing. When those two operations take place at the same site, the coils 3 or 4 are used as such. When the two sites are fairly remote from each other, it is necessary, in order to avoid excessive transport costs, to increase the weight/volume ratio by pressing the coils 3, 4 vertically so as to close up the turns which, due to their mode of manufacture, tend to form a spring. This operation may jam one or more badly placed turns and cause serious problems during unwinding. Because unwinding takes place by vertical traction on the wire starting from the center of the coil, there are risks of blockage, sudden winding off of several layers, formation of knots or breakage of wire. These mishaps may have serious consequences during wire-drawing or during the injection of aluminum wire into a ladle of molten steel for completing deoxidation.
This latter operation may be carried out with the aid of machines such as those described in French Pat. No. 2,112,093 dated Oct. 21, 1970, Pat. No. 2,184,456 dated May 15, 1972, Pat. No. 2,402,000 dated Sep. 2, 1977, Pat. No. 2,433,581 dated July 19, 1979 and Pat. No. 2,491,364 dated Oct. 3, 1980. These machines are designed mainly for flat elements, but they may use so-called machine wire, whatever the diameter thereof, depending upon the imperatives of price and the adjustment of speed for a predetermined rate in kg/min.
In order to avoid any sudden stoppage and subsequent mishaps, it is indispensable to be able to obtain satisfactory unwinding of the wire coil. At the present time, it appears that only the rosette-like helicoidal winding on a metal mandrel 1 (FIGS. 5 and 6) ensures satisfactory unwinding.
But such process requires considerable investment in special machinery, metal support mandrels and manpower. The cumbersome coils, having a fairly low weight/volume ratio (and hence considerable transport costs), generally are obtained from either a normal coil 2 (FIGS. 1 and 2) obtained by circular winding and spooling, or from coils obtained by helicoidal winding without a mandrel. They are then re-wound in rosette form, the wire being drawn from one and distributed on the second by means of a train of drive-presser rollers similar to that described in the above-mentioned French patents. This is an illogical and relatively expensive operation.
It is possible to unwind one or more wire coils 2, weighing one to two tons and obtained by normal winding, i.e. by spooled circular winding on horizontal axis. To unwind, the inverse operation must be carried out on a support with a horizontal reel, drawing the wire from the outside (FIGS. 7 and 8). The drawback of such method is the phenomenon of inertia arising from the weight and diameter of the wire coil and the speed of unwinding, and which increases as those parameters increase. It therefore is necessary to install on reel 5 (FIGS. 7 and 8) a brake 6 to be applied progressively or suddenly, in order to avoid the untimely unwinding of several turns and the risk of the formation of folds or knots in the wire. Such a reel is expensive and cumbersome. It often necessitates additional handling since the coils 2 frequently are delivered flat on pallets.
Tests heretofore made using a normally wound coil 2 (circular by spooling) placed on a fixed pallet 7 with its axis vertical (FIG. 9), by drawing the wire vertically from the center and causing it to pass over a guide drum 8, have not given encouraging results due to the incidence of simultaneous withdrawal of several turns which causes knots and blockage. Furthermore at the slightest incident, the final unwinding may experience a sudden collapse of the last five to ten windings, rendering them virtually unusable (FIG. 10). As a wound coil may comprise fifty to one hundred and twenty turns of a large diameter, depending on the height of the coil and the diameter of the wire, this frequent incident results in a considerable loss in weight, which is very expensive given the price of the metal.
It is the primary object of the present invention to unwind a coil of wire irrespective of its initial mode of winding, by means of a very simple apparatus without any mishap, by drawing the wire vertically from the center of the coil using the aforementioned patented machines.
In certain types of manufacture, for example wiredrawing, the rear end of the wire of one coil which is being unwound often is joined to the front end of a fresh coil. At the present time, this requires:
slowing down the reel supporting the coil being used PA0 stopping the machine during the joining operation PA0 starting up and accelerating the reel supporting the fresh coil. PA0 (a) placing a hollow coil of wire flat on a plate with the axis of its central hole disposed vertically, PA0 (b) holding the coil stationary during the course of unwinding by gripping it externally with a rigid device, PA0 (c) drawing the wire upwardly from the central hole while causing the unwinding turns to increase their curvature slightly by sliding over a horizontal pressure device extending over the top of the coil and bearing downwardly thereon, PA0 (d) passing the wire through an eyelet maintained above the coil and PA0 (e) then passing the wire over a rotatable guide drum. PA0 (a) a horizontal plate for supporting a coil-holding pallet, PA0 (b) a main vertical upright firmly affixed to the plate adjacent an edge thereof, PA0 (c) an articulated corset element constituted of horizontal cross-pieces mounted pivotally on the main upright, the cross-pieces comprising articulatory sections having vertical uprights, PA0 (d) actuating means operative to close the corset element to grip the coil externally and secure it against movement during unwinding and to open the corset element sufficiently to permit the introduction of a fresh coil on the plate, PA0 (e) a horizontal pressure device extending over the coil and being adapted to press downwardly thereon, said pressure device being movable vertically to advance to and retract from the top of the coil, PA0 (f) actuating means located internally of the main upright for moving the pressure device vertically, said means having a stroke sufficient to retract the pressure device to enable placement of a coil-holding pallet on the plate and to advance the pressure device to press against the top of the coil, PA0 (g) a rotatable guide drum located above the coil and PA0 (h) a stationary eyelet disposed intermediate the top of the coil and the guide drum, PA0 (i) said eyelet and guide drum being operative to guide the wire as it is withdrawn from the coil. PA0 (a) the plate is fixed and sealed to the floor, PA0 (b) the main vertical upright is hollow and has a square cross-section, and is provided with hinges for supporting pivotally at least two vertically spaced horizontal cross-pieces constituting the articulated corset element, PA0 (c) the articulatory cross-pieces of the corset element are constituted of arcuate sections supporting articular uprights adapted to bear against and grip the coil, whereby the coil is held rigidly by at least three vertical uprights spaced apart angularly about the perimeter of the coil, PA0 (d) the horizontal pressure device may constitute either a roller or a fork provided with two parallel prongs, PA0 (e) the actuating means for moving the pressure device urges that device against the top of the coil under pressure sufficient to maintain the stability of the coil during unwinding, there being at least one vertical slot in the main vertical upright to provide clearance for the vertical movement of the pressure device, PA0 (f) a horizontal support for the stationary eyelet is affixed to the upper part of the main vertical upright and PA0 (g) the guide drum is provided with spaced lateral flanges. PA0 (1) the profile and section of the metal wire, PA0 (2) the mode of winding the coil and PA0 (3) the weight and number of coils in use.
This involves loss of time. Furthermore, the inertia of the coil and its reel limits the speed, and especially variations in speed, of the unwinding.
It is a further object of the invention to avoid these drawbacks.
The process and apparatus of the invention are applicable to coils 2 or 3 of wire of standard diameter ranging from 9.5 to 19.5 mm, with the coils placed with their axes vertical on a handling pallet 7.